Air in - Air Out !!! The first thing you should do is put at least 4" exhaust on it and then maybe look into a cold air intake. If you can't get the air out, you won't get it in either, thus, slower spooling time! That will increase your off the line speed some. Also, the turbo resinator plug will help a little and costs only a couple bucks.
As for the Edge only reading 22.5 lbs. The other nite I smoked a 5.0 Mustang and saw 33 lbs as a guick glance and I believe it went higher. I was on #4 and didn't go a really long distance. It's funny how something like that only lasts a short time and you wonder how much boost, how high did EGT's go, and yet you want to watch the guy gettin smoked!!

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HAD - 94 Chevy Dually 4x4 - 6.5 Turbo
96 Chevy Ext.cab 4x4 - 6.5 Turbo
99 GMC Dually 4x4 - 6.5 Turbo
HAVE - 2005 GMC Sierra crew/6'box - 4X4 - Duramax w/Allison. Fully loaded - AiRaid intake - 4" Pinnicle Performance Exhaust (No Converter - Straight through muffler) - EGR blocker plate - Edge Juice w/attitude - 2" plug in Turbo Resinator -